Q QUANTILE RANGE

where q defines a quantile between 0 and 0.5 and
Xq denotes the q-th quantile of the data.

For example, if q = 0.20, then the q quantile range is
the difference between the 80th and 20th quantiles of the data. The
interquartile range is a special case of the q quantile range
with q = 0.25.

The q quantile range is used as a robust measure of scale.

Syntax:

LET <par> = Q QUANTILE RANGE <y>
<SUBSET/EXCEPT/FOR qualification>
where <y> is the response variable;
<par> is a parameter where the computed q
quantile range is stored;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

If <value> is between 1 and 100, it is interpreted as as
percentile (i.e., the quantile will be determined by dividing by
100). If <value> is between 0.5 and 1, then 1 - <value>
will be used. If <value> is less than or equal to 0 or
greater than or equal to 100, an error message will be printed.

Note:

Dataplot statistics can be used in a number of commands. For
details, enter